HELP |PLEASEEEE The perimiter of a rectangle is 42...

I

igor_iv837

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Help me please I can't get the answer

The perimeter of a rectangle is 42m. The length of the rectangle i 3 m less than twice the width. Find the length and width of the rectangle. THat's how i solved it....42=2w+3....It seems that its wrong cuz answer comes out wrong....HELP ME PLEASE?
 
Re: The perimiter of a rectangle is 42...

The perimeter of a rectangle is 42m. The length of the rectangle i 3 m less than twice the width. Find the length and width of the rectangle. THat's how i solved it....42=2w+3

You are not naming things.

Let width of rectangle be w.
Then length of rectangle is 2w-3.
Now, build your equation based on P = 2L + 2W
 
Re: The perimiter of a rectangle is 42...

Well that's what i got

P=42,

42=2(-3)+2(2w) The answer is w=12 ....its wrong in answer book it Length is 13m and Widths is 8
 
Help please

The perimeter of a rectangle is 42m. The length of the rectangle i 3 m less than twice the width. Find the length and width of the rectangle. THat's how i solved it....42=2w-3....It seems that its wrong cuz answer comes out wrong....HELP ME PLEASE?


They tried to help me with in intermediate algebra section but they dont know the answer either they gave me the formula of P=2L + 2W which doesnt work. ....I wrote out equation right but i can't solve it, 42 is the P, 2W is twice the width, and 3m less then which is -3 BUT I CAN"T SOLVE IT HELP PLZ
 
Re: Help please

igor_iv837 said:
The perimeter of a rectangle is 42m. The length of the rectangle is 3 m less than twice the width. Find the length and width of the rectangle. THat's how i solved it....42=2w-3....It seems that its wrong

They tried to help me with in intermediate algebra section but they dont know the answer either they gave me the formula of P=2L + 2W which doesnt work.
Click to expand...

Hello Igor:

What are you doing?

Your equation reflects the following statement.

"Three less than twice the width of a rectangle is 42 meters."

This is not what the exercise gives us. The exercise tells us that the PERIMETER is 42 meters. That's all the way around, both lengths and both widths added together.

The exercise gave you the perimeter, so the formula that you received on the other board for the perimeter is exactly where you need to start.

There are two steps to solving this exercise; it looks to me like you've mixed them together.

Use the perimeter formula to write an expression for L in terms of W.

Set the result equal to 2W - 3.

~ Mark :)

PS: Please do not post the same question in multiple locations.
 


From the Geometry/Trig board:
igor_iv837 said:
The perimeter of a rectangle is 42m. The length of the rectangle is 3 m less than twice the width. Find the length and width of the rectangle. THat's how i solved it....42=2w-3....It seems that its wrong

They tried to help me with in intermediate algebra section but they dont know the answer either they gave me the formula of P=2L + 2W which doesnt work.
Click to expand...

Hello Igor:

What are you doing?

Your equation reflects the following statement.

"Three less than twice the width of a rectangle is 42 meters."

This is not what the exercise gives us. The exercise tells us that the PERIMETER is 42 meters. That's all the way around, both lengths and both widths added together.

The exercise gave you the perimeter, so the formula that you received on the other board for the perimeter is exactly where you need to start.

There are two steps to solving this exercise; it looks to me like you've mixed them together.

Use the perimeter formula to write an expression for L in terms of W.

Set the result equal to 2W - 3.

~ Mark :)

PS: Please do not post the same question in multiple locations.
 
Re: The perimiter of a rectangle is 42...

igor_iv837 said:
... 42=2(-3)+2(2w)
Click to expand...

Okay, now I see what's going on. You make it confusing for me when you try to conduct a discussion in two different places.

You did not make the substitution correctly.

You need to substitute the correct expression for the length into the perimeter formula.

What you wrote tells me that you think the length is negative three meters.

Good grief; what's going on here (that is a rhetorical question). Are you just guessing?

~ Mark :?
 
No i'm not guessing!!! Tomorrow is math class AND I cannot understand it at all, i'm sitting here already hours trying to understand and tomorrow got to wake up at 5 am. ....I can't understand the whole concept and how to use the formula right....I wrote the equation right but can't get to the answer 42=2x-3w :(( :( i suck!!!
 
Try to remain calm ...

igor_iv837 said:
I wrote the equation right but can't get to the answer 42=2x-3w
Click to expand...

No, you did not write the equation properly.

As I said before, there are TWO steps. I'll use Loren's approach from now on.

You've got the first part of the first step correct.

1) L = 2W - 3

You wrote the equation above from the given information. This is convenient because it gives us an expression that represents L by using W instead. This expression is 2W - 3.

We can now write 2W - 3 instead of writing L.

We have the perimeter equation.

2L + 2W = 42

We cannot solve this equation as it is to find the values of L and W because there are two unknowns. We need an equation that contains only one variable.

You have an expression for L that contains only W. Can you "see" that if you substitute this expression for L in the perimeter equation (i.e., write the equivalent of L which is 2W - 3 in place of the symbol L) that you will end up with an equation that contains only W?

That is the goal of step one. Get an equation with only one variable.

NEXT comes step 2.

Once you have properly substituted the expression for L into the perimeter equation, then solve the resulting equation for W. Once you get the value for W, you can find L by using the definition L = 2W - 3.

I'm curious to know what you were thinking when you substituted -3 for L ...

~ Mark :|
 
igor_iv837 said:
AND IT TAKES ETERNITY FOR YOU GUYS TO ANSWERRRR WHAT AM I SUPPOSED TO DO?????
Click to expand...
Since you regard ten minutes (the length of time between your first post and your first reply) as "an eternity", obviously you overlooked major parts of the "Read Before Solution" post that you read before posting:

Have patience. There is no paid staff waiting on-hand to give instant replies. Many of the volunteer tutors have "real" jobs, and they all have to sleep from time to time. The people "viewing" your posts may be fellow students. Please don't be offended if there are "views" but no replies. It may take hours, even days, for a tutor, qualified in your topic's area, to respond.
Click to expand...
Since you clearly require on-demand instant replies, you will need to contract with a service which offers such.

Also, since you have made quite clear that you have no understanding of any of the required material, you will need to contract with a service which (or personal tutor who) provides actual course instruction, not "just" homework help (as is offered here, and indeed is "all" that is offered at pretty much all online tutoring services). Your local Kumon Tutoring Centre might be one useful resource; check your local "yellow pages".

You should expect to need to set aside a few hours a week (an hour or two a day would be best) for concentrated re-teaching. With some luck, a good private instructor, and a lot of hard work, you may be able to get caught up to your class in only a few weeks.

Our best wishes to you in your studies.

Eliz.
 
Code: 
..........2w - 3..........
.                        .
w                        w
.                        .
..........2w - 3..........
Igor, Igor, Igor, OH Igor :shock:
You seem to be going 100 miles an hour, but ending up behind your starting point :wink:

Look at the rectangle above: you agreed the width = w, then the length = 2w - 3
And we're told the perimeter (that's ALL THE WAY AROUND!) is 42.
ALL THE WAY AROUND means 2 times the width plus 2 times the length: you OK with that?

So we have 2 times w + 2 times (2w - 3) = 42 : OK?
That's 2w + 2(2w - 3) = 42 : OK?
2w + 4w - 6 = 42 : OK?
6w = 48 : OK?
w = 8 : OK?
So width = 8, and length = 2w - 3 = 16 - 3 = 13 : OK?

CHECK: 8 + 8 + 13 + 13 = 42 : SUCCESS :idea:

By the way, I had a moment of weakness: don't expect us to conduct classroom education here :shock:
 
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